No one ever thought they'd see Led Zeppelin play again... but there they were, onstage in London last November. Now the Chipmunks—who cover Led Zep's “Rock and Roll” on their new album Undeniable—follow suit with a surprise reunion of their own. After a difficult weeklong estrangement, America's favorite musical squeakers welcome longtime frontman Alvin back into the fold. The Chipmunks can once again be known as Alvin and the Chipmunks.

“I'm back!” says Alvin. “Did you miss me?”

Rumored to be fielding movie and television show offers in the wake of 2007's box office smash Alvin and the Chipmunks (and its accompanying Top 5 soundtrack), Alvin took his hula hoop and vanished without warning just after the band completed UNDENIABLE. Simon, Theodore and longtime producer David Seville subsequently held open auditions for the job, including fan submissions via YouTube.

“We want to thank all the little munks and munkettes who sent us videos,” says Simon. Adds Dave Seville, “I'll be keeping them on file in the studio. Next time Alvin disappears, you just might hear from me. You got that Alvin?... Alvin?... AAAAAAALVIN! Oh well,” Seville continues. “You may hear from me shortly.”

Even as the first video from UNDENIABLE came out—a version of the disco classic “Shake Your Groove Thing” featuring guest vocals by Drew Seeley (High School Musical soundtracks, Another Cinderella Story)—the three Chipmunks had been spotted doing lunch at The Ivy. “Just family catching up,” Simon told Rodent Defamer at the time. But it seems the gossip was all true.

“When they started having those auditions, I was a little shaken” Alvin admits. My brothers and I met at The Ivy without managers or agents and remembered what's important: family and music. I've been in this band for five decades, and I intend to be in this band another five decades. Simon can probably tell you what that is in chipmunk years.”

“Beats me,” says Simon. “You think I know that just because I wear glasses?” “Rock'n'roll keeps us young!” says Theodore.

Indeed—since beginning their career with the chart-topping, Grammy-winning hit “The Chipmunk Song (Christmas Don't Be Late),” the trio has successfully reinvented itself on more than 40 albums, including forays into country, disco, metal, punk and hip-hop. Like its predecessors, UNDENIABLE showcases a band that's mastered every style, from the funky title track and remix of “We're The Chipmunks” (the theme song from the popular cartoon series) to a moving version of Bob Marley's “Three Little Birds.” There's also an epic take on Bon Jovi's “Livin' On a Prayer,” a new holiday hit in “Ho Ho Ho” and what just might be the definitive version of “Don't Stop Believin'”.